Field of the Invention
The present invention relates to a method for modifying starch to slow down the digestion rate, which belongs to the field of modified starch.
Description of the Art
Starch, as a main source of energy for humans and most animals, is commonly used in food, medicine, textile and other industrial fields. In today's society, consumers are increasingly pursuing higher quality nutrition. Foods, which can maintain satiety and provide energy continuously and slowly after intake, satisfy the needs of consumers. The slowly digestible starch, which is slowly absorbed after being ingested by the human body, provides sustained release of energy to avoid the severe fluctuation of the blood sugar. Conforming to the trend of food development, it has great market potential as a raw material for food.
However, in the process of food processing, such as heating, irradiation, and decoction, the structure of starch granules is destroyed and the slow digestibility of the processed starch is drastically reduced, making it difficult to meet the requirements of modern consumers. The modification of starch by physical, chemical or biological methods can change the molecular structure of starch, thereby improving the digestibility of starch and meeting the needs of a healthy diet. Biological methods, which have the advantage of substrate specificity, are most widely used.
Starch branching enzyme (BE; EC 2.4.1.18) is a glycosyltransferase belonging to glycoside hydrolase 13. It firstly hydrolyzes α-1,4 glycosidic bonds on the substrate molecule and cleaves straight-chain dextran. It, in turn, transfers the sugar chain fragments to the remaining substrate molecules by transglycosylation, forming α-1,6 glycosidic bonds.
In the previous report, the method of starch modification using the starch branching enzyme are relatively simple, and still has room for improvement. The invention improves the slow digestibility of the modified starch by optimizing the enzymatic modification process.